The following layout test is flaky on Mac and is crashing periodically (though not often). svg/css/font-face-crash.html Probable cause not apparent. Example stack: crash log for DumpRenderTree (pid 2816): STDOUT: <empty> STDERR: SHOULD NEVER BE REACHED STDERR: ../../third_party/WebKit/Source/WebCore/platform/graphics/mac/ComplexTextController.cpp(248) : int WebCore::ComplexTextController::offsetForPosition(float, bool) STDERR: 1 0x6d76e77 WebCore::ComplexTextController::offsetForPosition(float, bool) STDERR: 2 0x6d949b3 WebCore::Font::offsetForPositionForComplexText(WebCore::TextRun const&, float, bool) const STDERR: 3 0x6bb50ed WebCore::Font::offsetForPosition(WebCore::TextRun const&, float, bool) const STDERR: 4 0x85e1c90 WebCore::InlineTextBox::offsetForPosition(float, bool) const STDERR: 5 0x88ddcf0 WebCore::RenderText::positionForPoint(WebCore::LayoutPoint const&) STDERR: 6 0x96da5fd _ZN7WebCoreL40selectionExtentRespectingEditingBoundaryERKNS_16VisibleSelectionERKNS_11LayoutPointEPNS_4NodeE STDERR: 7 0x96d9bfe WebCore::EventHandler::updateSelectionForMouseDrag(WebCore::HitTestResult const&) STDERR: 8 0x96d8eae WebCore::EventHandler::handleMouseDraggedEvent(WebCore::MouseEventWithHitTestResults const&) STDERR: 9 0x96df46f WebCore::EventHandler::handleMouseMoveEvent(WebCore::PlatformMouseEvent const&, WebCore::HitTestResult*, bool) STDERR: 10 0x96de953 WebCore::EventHandler::mouseMoved(WebCore::PlatformMouseEvent const&) STDERR: 11 0x65f575f WebKit::PageWidgetEventHandler::handleMouseMove(WebCore::Frame&, WebKit::WebMouseEvent const&) STDERR: 12 0x65f543f WebKit::PageWidgetDelegate::handleInputEvent(WebCore::Page*, WebKit::PageWidgetEventHandler&, WebKit::WebInputEvent const&) STDERR: 13 0x673a09b WebKit::WebViewImpl::handleInputEvent(WebKit::WebInputEvent const&) STDERR: 14 0x4b1a801 WebTestRunner::EventSender::doMouseMove(WebKit::WebMouseEvent const&) STDERR: 15 0x4b19e0b WebTestRunner::EventSender::replaySavedEvents() STDERR: 16 0x4b17b25 WebTestRunner::EventSender::mouseUp(std::vector<WebTestRunner::CppVariant, std::allocator<WebTestRunner::CppVariant> > const&, WebTestRunner::CppVariant*) STDERR: 17 0x4b220eb WebTestRunner::CppBoundClass::MemberCallback<WebTestRunner::EventSender>::run(std::vector<WebTestRunner::CppVariant, std::allocator<WebTestRunner::CppVariant> > const&, WebTestRunner::CppVariant*) STDERR: 18 0x4b0a9ca WebTestRunner::CppBoundClass::invoke(void*, _NPVariant const*, unsigned long, _NPVariant*) STDERR: 19 0x4b0a4eb WebTestRunner::CppNPObject::invoke(NPObject*, void*, _NPVariant const*, unsigned int, _NPVariant*) STDERR: 20 0x8dcd3cf _ZN7WebCoreL18npObjectInvokeImplERKN2v89ArgumentsENS_18InvokeFunctionTypeE STDERR: 21 0x8dcc66c WebCore::npObjectMethodHandler(v8::Arguments const&) STDERR: 22 0x2f0ec36 _ZN2v88internalL19HandleApiCallHelperILb0EEEPNS0_11MaybeObjectENS0_12_GLOBAL__N_116BuiltinArgumentsILNS0_21BuiltinExtraArgumentsE1EEEPNS0_7IsolateE STDERR: 23 0x2f0e6da _ZN2v88internalL26Builtin_Impl_HandleApiCallENS0_12_GLOBAL__N_116BuiltinArgumentsILNS0_21BuiltinExtraArgumentsE1EEEPNS0_7IsolateE STDERR: 24 0x2f03fdc _ZN2v88internalL21Builtin_HandleApiCallENS0_12_GLOBAL__N_116BuiltinArgumentsILNS0_21BuiltinExtraArgumentsE1EEEPNS0_7IsolateE STDERR: 25 0x3d10a216 STDERR: 26 0x5248d42d STDERR: Received signal 11 SEGV_MAPERR 0000bbadbeef STDERR: [0x00000291a71f] STDERR: [0x00000291a6bb] STDERR: [0x00000291a34b] STDERR: [0x0000983c859b] STDERR: [0x0000ffffffff] STDERR: [0x000006d949b3] STDERR: [0x000006bb50ed] STDERR: [0x0000085e1c90] STDERR: [0x0000088ddcf0] STDERR: [0x0000096da5fd] STDERR: [0x0000096d9bfe] STDERR: [0x0000096d8eae] STDERR: [0x0000096df46f] STDERR: [0x0000096de953] STDERR: [0x0000065f575f] STDERR: [0x0000065f543f] STDERR: [0x00000673a09b] STDERR: [0x000004b1a801] STDERR: [0x000004b19e0b] STDERR: [0x000004b17b25] STDERR: [0x000004b220eb] STDERR: [0x000004b0a9ca] STDERR: [0x000004b0a4eb] STDERR: [0x000008dcd3cf] STDERR: [0x000008dcc66c] STDERR: [0x000002f0ec36] STDERR: [0x000002f0e6da] STDERR: [0x000002f03fdc] STDERR: [0x00003d10a216] STDERR: [0x00005248d42d] STDERR: ax: bbadbeef, bx: ed710101, cx: ed7101e6, dx: ed7101e6 STDERR: di: 0, si: 9b6284b, bp: c007da48, sp: c007d970, ss: 23, flags: 210282 STDERR: ip: 6d76e81, cs: 1b, ds: 23, es: 23, fs: 0, gs: f